Stencil sheet



Patented July 15, 1930 PATENT OFFICE SHINJIRO HORII, 0F TOKYO, JAPAN STENCIL SHEET .No Drawing.

My invention relates to improvements in stencil sheets for use in duplicating manuscript and typewritten documents, drawings and like, consisting of a sheet of fibrous material coated or impregnated with a coating composition which is impermeable to ink and can be stencilized b the pressure of the stylus or the impact of t ie type ofa writing machine.

It has previously been proposed to rovide a stencil sheet of this kind, such as a ass of fibrous material coated with a medium which includes a cellulose ester, such as cellulose nitrate or acetate, and a tempering agent, such as castor oil or other oily materials.

It has furthermore been roposed to provide such a stencil sheet of a fibrous base, such as yoshino paper, which is coated with a com position including a derivative of cellulose, oxycellulose or hydro-cellulose, the substance or composition being dissolved in a volatile solvent, such as ether-alcohol mixture, amyl acetate, and a tempering agent, such as resins, fatty oils, solid fatty acids and similar hydrocarbons.

It has furthermore been proposed to provide a stencil sheet adapted to be impressed by type and comprising a porous base having a coating which includes a gelatinizing organic colloid, such as gelatine, dispersable in water, in association with an oily material a such as sperm oil as the main tempering agent, and a sulphonated liquid Wax as an emulsifying agent.

According to the present invention the stencil sheet comprises a fibrous base coated with a coating material consisting of a solution of esters of polysaccharides in a volatile solvent, in admixture with a liquid wax.

The liquid waxes consist of the liquid esters of the higher fatty acids and the higher saturated monatomic alcohols, and, therefore difier sharply from the glycerides of acids;

fatt

The liquid waxes are further readily dis-- Application filed October 8, 1927. Serial No. 225,028.

tinguished from the fatty oils by their low specific gravities. It is notable that their viscosity is much less influenced by variations of temperature than is the case with fatty oils. The liquid waxes absorb very little oxygen Cflrom the atmosphere and therefore do not he typical liquid waxes are sperm oil and Arctic sperm oil (bottlenose oil). 4 In carrying out this invention, a sheet of fibrous base, such as Japanese yoshino paper, is coated or impregnated with a coating material prepared by dissolving esters of polysaccharides, such as starch acetates, mannan acetate, cellulose acetate, and cellulose nitrate, in suitable solvents and diluents, such as acetone, ethyl alcohol, butyl alcohol, benzyl alcohol, ethyl acetate, butyl acetate, amyl acetate, benzene and, toluene,-or a mixture of them, a liquid wax, being added. Ifnecessary, a tempering agent, such as fatty oils, fats, waxes, naphthenic acid glycerides, nahpthenic acid and fatty acids, may be added to the coating composition. The

paper base may be coated or impregnated in any desired manner with the composition above described. Or, the composition may be added to the paper stuff in a mixing hollander during the paper making operation.

The proportions of the ingredients of the coating composition may vary according to circumstances. The following is an example:

Parts by weight Cellulose nitrate l0 Ethyl alcohol 5 Butyl alcohol 1O Ethyl acetate 15 Butyl acetate 30 Benzene 25 Toluene 25 Sperm oil 20 Naphthenic acid glycerides 5 Oleic acid 5 The term esters of polysaccharides is in- 2. A stencil sheet adapted for stencilizing tended to include not only one of definite esby ressure comprising a base of fibrous maters of polysaccharides, but also a mixture of terial coated or impregnated with a composithem. tion including esters of polysaccharides, a

In the present invention the coating mateliquid wax and a tempering a ent. rial is remarkably fluid owing to the smaller Y 3. A tencil sheet adapted or stencilizing viscosity of the liquid waxes. Hence, a comby pressure comprising a base of fibrous maposition of hi her concentration may be obterial coated or impregnated with a compositained, with t e result that a thick coatin tion including esters of polysaccharides, a

moderately soft and pliable is obtaine liqilld wax and a fatty tempering agent.

Moreover, the coating is permanent and is n testimony whereof I afiix my s1 ature. not affected by changes of temperature, per- SHINJIRO H RH. mitting clear writings by the pressure of a writingbmachine.

As a ove referred to, the employment of liquid waxes in association with gelatinizing organic colloids, such as elatine, dispersed in water has been propose in the production of stencil sheets. In this connection, it is found that the coating composition is an I emulsified mixture, and after the evaporation of water, there remains a coating consistin of a mixture of the liquid waxes and the co loids. However, the liquid waxes and the colloids do not form a homogeneous body and moreover, the compound is liable to become hard and brittle and to separate out the oily material while being stored.

According to the present invention, on the contrary, esters of polysaccharides are used, instead of gelatinous organic colloids, in association with liquid waxes, and the solo tion of these ingredients in volatile solvents forms a true solution. After the evaporation of the solvents there remains a liable mo uniform coating which is more durab e and stronger than where gelatinous organic colloids are used. The liquid wax moderately softens the coating and prevents the film from being too tough and not allowing the ty to cut through.

urthermore, it has sometimes been observed that the coating surface of stencil sheets having a coating composition of cellulose esters and fatty acid glycerides, become no sticky and evolves a rancid smell, especially in the case of improperly prepared cellulose esters. This is due to t e decomposition of cellulose esters started and accelerated by the rancidity of the fatty acid glycerides. In I accordance with the present invention, the

coating composition consists chiefly of esters of lysaccharides and a liquid wax, instead of atty acid glycerides. Liquid wax is not liable to become rancid and, consequently, no

will not produce the decomposition of esters of polysaccharides and thereby the above deterioration of the coating surface of the stencil sheets.

What I claim is 1. A stencil sheet adapted for stencilizing by pressure comprising a base of fibrous material coated or impregnated with a composition including esters of polysaccharides and a liquid wax. 

